Computer applications often have bottlenecks that may limit the throughput or efficiency of an application. Often, bottlenecks may not be fully appreciated when the application code is being written and may only be noticeable when the code may be executed under load.
The bottlenecks may be an artifact of the application design, poor programming technique, or may be the result of outside constraints on an application. When a bottleneck may be identified, a programmer may be able to investigate the bottleneck and rewrite or otherwise improve the code to increase application performance.